1. Field of the Invention
This invention relates to an orthodontic buccal tube having a first passage for receiving a main arch wire, a second passage for a lip bumper or headgear wire and a third passage for an auxiliary arch wire.
2. Description of the Related Art
Orthodontic treatment often involves the use of tiny brackets that are secured to anterior, cuspid and bicuspid teeth. A main arch wire is placed in slots of the brackets to form a track to guide movement of the teeth toward desired positions. Ends of the main arch wire are held in passages formed in small appliances known as buccal tubes that are secured to molar teeth.
Some buccal tubes have passages in addition to the passage for the main arch wire. For example, a passage having a rectangular cross-section may be provided for an auxiliary segmented or utility arch wire that may be used in conjunction with the main arch wire on either the upper or the lower arch. As another option, a round passage may be provided to receive the ends of a facebow or a lip bumper. The facebow is an appliance for the upper arch that is connected to headgear or a neck band to urge the upper arch in a distal, or rearward direction in the mouth. A lip bumper is an appliance fitted between the lower lip and front lower teeth for urging the lower arch in a distal direction.
The space available in the oral cavity next to the molar teeth for receiving buccal tubes is normally limited, and consequently it is desirable to avoid the use of buccal tubes that are relatively bulky. For example, larger buccal tubes when used on the upper arch may rub against the cheek and cause discomfort to the patient. On the lower arch, it is desired to not only avoid impingement with the cheeks but also to avoid contact with any overhanging portion of the cusp of the upper molars when the jaw is closed. In U.S. Pat. No. 4,820,151, assigned to the assignee of the present invention, a hook for anchorage of elastic bands or other auxiliary appliances is gingivally inclined to avoid occlusal interference.
U.S. Pat. No. 4,963,092, also assigned to the assignee of the present invention, describes a buccal tube having a first passage for a main arch wire and a second passage alongside the first passage. The second passage includes a mesial cylindrical portion for receiving ends of a facebow or a lip bumper. The second passage also includes a distal rectangular portion aligned with the cylindrical portion for receiving an auxiliary rectangular arch wire. However, while the buccal tube described in U.S. Pat. No. 4,963,092 has a relatively compact configuration that is advantageous in many instances, an auxiliary arch wire cannot be used simultaneously with use of either a facebow or lip bumper.
A buccal tube described in U.S. Pat. No. 5,057,012 has a first passage for a main arch wire and a second passage for a lip bumper or facebow. The second passage is flared from the distal end to the mesial end, and the mesial end is oval. It is asserted in U.S. Pat. No. 5,057,012 that such construction enhances insertion of a lip bumper or facebow.
However, there exists a need in the art for an orthodontic buccal tube having three passages that can be used simultaneously when desired, and yet is relatively compact in order to fit within the confines of the oral cavity while avoiding contact with opposing teeth, adjacent tissue or otherwise causing discomfort to the patient. Moreover, since lip bumpers or facebows are typically inserted into the tubes by the patient each night before sleeping, it would be desirable to provide a tube that is easy for the patient to use.